Related Experiment Videos
Diurnal variation of peak expiratory flow rate in asthmatic children
Insights
Asthmatic children exhibit a significant daily rhythm in peak expiratory flow rate (PEFR). This diurnal variation, with a trough around 3:45 AM, was consistent across participants and inversely related to lung function.
Area of Science:
- Pediatric Pulmonology
- Chronobiology
- Asthma Research
Background:
- Diurnal variation in peak expiratory flow rate (PEFR) is known in adults but not well-characterized in children.
- Previous data suggest a similar rhythm in pediatric populations, necessitating formal investigation.
Purpose of the Study:
- To characterize the diurnal rhythm of PEFR in asthmatic children.
- To analyze the amplitude, timing, and influencing factors of this daily variation.
Main Methods:
- Sixty-eight asthmatic children self-recorded PEFR three times daily for four weeks.
- Statistical analyses included paired t-tests, cosinor analysis, and spectral analysis.
Main Results:
- 73.5% of children showed significant diurnal PEFR variation.
- The average amplitude was 22.6% of mean PEFR, with a group trough at 03:45 AM.
- Spectral analysis confirmed a 24-hour period; amplitude correlated inversely with lung function.
Conclusions:
- Asthmatic children exhibit a robust diurnal PEFR rhythm, similar to adults.
- The amplitude of this rhythm is influenced by overall lung function, not age, sex, or medication.
- Understanding this circadian pattern is crucial for asthma management in children.
Abstract:
A diurnal variation in peak expiratory flow rate (PEFR) has been described in normal and asthmatic adults. This variation has been apparent in data reported from children, but the rhythm has not been characterized. Sixty-eight asthmatic children recorded PEFR three times a day for 4 weeks at home. Data were analyzed using paired t-tests, cosinor analysis, and spectral analysis. Fifty subjects (73.5%) had significant diurnal variations in PEFR on paired t-tests. Mean amplitude, derived from cosinor analysis, was 22.6% (SD = 13.2%) of mean PEFR. The trough of the PEFR rhythm occurred at 0345 hours for the group. Spectral analysis confirmed that the major component of the variation in PEFR was due to a rhythm with a period of 24 hours. The amplitude of the diurnal variation was not related to the subjects' age, sex, or medications taken but was inversely related to mean lung function (expressed as percentage predicted).